Recent medical studies have found that antibiotic resistant bacterial organisms are becoming more and more prevalent. Most bacterial infections are cultured and the type of bacteria causing the infection identified before an antibiotic treatment is prescribed. Infections of the middle ear (i.e., otitis media) are one of the few bacterial infections which are routinely treated without first being cultured and the bacterial strain identified. In general, without a pre-treatment identification of each bacterial strain present in the infected area, there is a risk that the chosen antibiotic treatment will be ineffectual. This risk has increased with the ever increasing number of antibiotic resistant bacteria. Depending on the type of infection, prescribing an ineffectual treatment can unnecessarily prolong a patient's pain and suffering and may even result in further complications from recurrent otitis media.
One main reason bacterial ear infections are typically not cultured and identified before being treated is because the ability to aspirate a specimen from the middle ear space has been limited by the equipment and devices previously used for that purpose. One such prior aspirator had a handle at one end which was connected to a vacuum pump, a hollow needle at its other end and a vial attached to the handle for collecting aspirated fluid. The needle was inserted through a patient's ear drum (i.e., tympanic membrane) and the vacuum pump was operated to establish a vacuum used to withdraw fluid from the middle ear space and collect the fluid in the vial. One problem with this type of collection system is the need for an external vacuum pump. Such mechanical vacuum pumps are expensive and not always available when and where needed, for example, in many less developed countries and underserved areas of even major industrialized countries. Because some type of tubing and connector is needed to connect the aspirator to the external vacuum pump, this type of collection system can be cumbersome and unwieldy, making it difficult to collect a specimen of middle ear fluid.
An aspirator which does not require an external vacuum source is disclosed in U.S. Pat. No. 4,641,663. This aspirator is a hypodermic needle assembly with a plunger which is spring loaded to draw fluid through its hollow needle once a latch mechanism is released. While this type of aspirator is self-contained (i.e., does not use an external suction pump or vacuum source) and disposable, this aspirator is still relatively complex and, thus, expensive to manufacture. A problem shared by both of the above described prior aspirators is that the depth of penetration by the hollow needle, into the middle ear space, is largely dependent on the skill and experience of the person performing the procedure. Thus, the use of either of these aspirators is likely to be limited to only the most experienced practitioners.
Therefore, especially with the apparent continued proliferation of antibiotic resistant bacteria, there is an increasing need for a disposable and inexpensive apparatus for aspirating and collecting a fluid specimen from the middle ear space of a patient without the need of an external vacuum source (i.e., self-contained). There is a further need for such an apparatus which does not rely solely on the practitioner's skill to determine the depth of penetration through the ear drum.